The advance by the forces of UN-recognised Government of National Accord (GNA) came less than a week after the warlord Khalifa Haftar declared himself the ruler of Libya.
Forces of Libya's UN-recognised Government of National Accord (GNA) took control of two fronts early on Friday in the south of the capital Tripoli.
"Our forces made progress on the Mashru and Hallatat fronts and took a large area under control," Mustafa al Majai, spokesman for the GNA’s Burkan Al Ghadab (Volcano of Rage) operation, told Anadolu Agency, adding the areas had been out of their control for three months.
He said they have also taken the Hamza camp in the south of Tripoli.
The GNA accuses several regional and European countries of providing military support to militias loyal to warlord Khalifa Haftar, who contests the GNA's legitimacy and authority in the oil-rich country.
On Monday, Haftar declared himself the ruler of Libya, claiming that he "accepted the mandate of the Libyan people" and terming the 2015 UN-brokered Skhirat agreement for a unified government in the country "a thing of the past."
Since the ouster of late ruler Muammar Gaddafi in 2011, two seats of power have emerged in Libya: Haftar in eastern Libya, supported mainly by Egypt and the UAE, and the GNA in Tripoli, which enjoys UN and international recognition.
Haftar’s self-proclaimed Libyan National Army (LNA) launched a failed offensive to take Tripoli last April which caused bloodshed and suffering but stalled on the outskirts of the city.